Final volume levels for short film project

Hey Café LA folks!

I am really scratching my head over a question I have, and Google is providing very different answers... I'll tell you my situation.

I'm editing a short film in FCP7. The film's soundtrack is a music track mixed with a voice-over—no dialogue. We put the vox and music together in Logic and are ready to bounce it out to stick into FCP for final output.

I will then be transferring to film to HDCAM and DigiBeta for festival play.

My question is, what is an ideal peak volume level limit for the bounce? Obviously I don't want it to distort but I'm worried about it being too quiet, too. I know there's no hard and fast rule for this. But the volume level is faiiiirly consistent throughout the film. I sort of guessed from my research that -6db to -8db (on the FCP scale, with 0 being the absolute top) would work. But this is entirely guesswork, and like I said I'm worried about it being too quiet, so would a pro be willing to help me out?

Thanks a million,

Mark